This article brings empirical support for the projection of a Commitment Phrase (CommitP) in the field that maps the conversational pragmatics at the left periphery of clauses. Krifka (2015, 2019, 2020) proposes CommitP as a projection that maps the speaker’s commitment to act on the proposition insofar as s/he has evidence for the truth-condition or expects the addressee to produce and commit to such evidence. CommitP replaces Ross’s (1970) idea that the speaker-hearer is related to the proposition by a speech-act predicate such as declare. Krifka argues for the alternative approach primarily on theoretical grounds. This article verifies and validates this proposal on the basis of Japanese sentence final particles and Romanian speech act particles. We extend our analysis beyond these languages that overtly mark the CommitP to a language such as English, which does not, by proposing an analysis of so-called biased questions that incorporates the CommitP.